621.312134     G    
           Gurley , firm , math . instr.makers, Troy. 
                  (1921 . W .  y L . E . Gurley )
                   Manuel of Gurley hydrsulic engineering instru-
            ments .  2d .   ed . . . .    Troy ,  N . Y . W . y L. E .
             Gurley  [ c1921 ]
                      1  p . 1 . ,  [7 ] -155 ,  [ 3] p . 1  1 . front . 
              (Facsin)   illus . , forms, diagrrs .   23 cm .